Icosavax Highlights Six Months Durability Data For Respiratory Syncytial Virus Vaccine Candidate

Icosavax Inc ICVX provided a six-month immunogenicity update from its Phase 1/1b trial of IVX-121 against Respiratory Syncytial Virus (RSV).
These new data demonstrate a sustained neutralizing antibody (nAb) response against RSV, lasting at least six months after a single administration of IVX-121.
IVX-121 continued to be generally well-tolerated, with no safety concerns observed in this six-month follow-up and no vaccine-related serious adverse events (SAEs).
In these day 180 immunogenicity data across IVX-121 unadjuvanted dosage groups, the durability pattern was comparable in both young and older adult groups.
In the older adult portion of the study (Phase 1b), geometric mean titers (GMTs) for RSV-A nAbs that were previously reported at up to 7,561 IU/mL at day 28 were observed to persist at up to 6,184 IU/mL through day 180.
GMTs for RSV-A at day 180 was maintained within a range of 64-98% relative to the previously reported GMTs at day 28.
GMTs for RSV-B showed greater variability but were maintained above baseline through day 180.
Icosavax plans to provide a 12-month immunogenicity update from an extension of this Phase 1b trial in mid-2023.
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